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991.
Hydrogen‐Bonding‐Mediated Synthesis of Atomically Thin TiO2 Films with Exposed (001) Facets and Applications in Fast Lithium Insertion/Extraction 下载免费PDF全文
Dr. Hongye Zhang Dr. Zhenzhen Yang Wei Gan Dr. Yanfei Zhao Dr. Bo Yu Huanjun Xu Zhishuang Ma Leiduan Hao Dechao Chen Dr. Shiding Miao Prof. Zhimin Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14608-14613
Ultrathin two‐dimensional (2D) crystalline materials show high specific surface area (SA) of high energy (HE) facets, imparting a significant improvement in their performances. Herein we report a novel route to synthesize TiO2 nanofilms (NFs) with atomic thickness (<2.0 nm) through a solvothermal reaction mediated by the hydrogen‐bonding networks constructed by hydroquinone (HQ). The resultant TiO2 NFs have nearly 100 % exposed (001) facets and give an extremely high SA up to 487 m2 g?1. The synergistic effect of HQ and choline chloride plays a vital role in the formation of TiO2 NFs and in the exposure of HE (001) facets. Because of its ultrathin feature and exposed (001) facet, the N2‐annealled TiO2 NFs showed fast kinetics of lithium insertion/extraction, demonstrating foreseeable applications in the energy storage. 相似文献
992.
以FeSO4·7H2O、NH4H2PO4、H2O2、Li2CO3、C6H12O6和自制的氧化石墨烯(GO)为原料,分别采用原位包覆法和非原位包覆法制备了石墨烯磷酸铁锂样品:LiFePO4/C/G-1和LiFePO4/C/G-2。用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、交流阻抗(EIS)和充放电测试研究了两种包覆方法制备的样品的晶体结构、形貌和电化学性能。结果表明原位法包覆所得复合材料LiFePO4/C/G-1具有更优秀的电性能:在2.5~4.1V充放电,0.1C和1C首次放电比容量分别为158.15和150.5mAh·g-1,在1C倍率下循环500次后容量保持率达到98.3%。 相似文献
993.
Weibo Hua Yanjie Wang Yanjun Zhong Guoping Wang Benhe Zhong Baizeng Fang Xiaodong Guo Shixuan Liao Haijiang Wang 《中国化学》2015,33(2):261-267
To explore advanced cathode materials for lithium ion batteries (LIBs), a nanoarchitectured LiNi1/3Co1/3Mn1/3O2 (LNCM) material is developed using a modified carbonate coprecipitation method in combination with a vacuum distillation‐crystallisation process. Compared with the LNCM materials produced by a traditional carbonate coprecipitation method, the prepared LNCM material synthesized through this modified method reveals a better hexagonal layered structure, smaller particle sizes (ca. 110.5 nm), and higher specific surface areas. Because of its unique structural characteristics, the as‐prepared LNCM material demonstrates excellent electrochemical properties including high rate capability and good cycleability when it is utilized as a cathode in the lithium ion battery (LIB). 相似文献
994.
通过溶胶-凝胶法制备了Li2FeSiO4@C/CNTs(LFS@C/CNTs)纳米复合材料,其中三嵌段共聚物P123用作结构导向剂和碳源,碳纳米管作为导电线提高材料的导电性。LFS@C/CNTs不仅具有海绵状纳米孔,能够与电解液充分接触改善锂离子的传输路径,同时由非晶碳和碳纳米管构成的三维桥联导电网络利于电子的快速传递,提高了材料大电流充放电能力和循环稳定性。复合后的LFS@C/CNTs的高倍率性能相比LFS@C明显提高, 当CNTs的掺量为4%,电压窗口为1.5~4.5 V,0.1C电流密度下放电比容量为182 mAh·g-1。在10C经70次循环后该材料的放电比容量能保持在117 mAh·g-1,是LFS@C放电比容量(55 mAh·g-1)的两倍。 相似文献
995.
Dianions as Formal Oxidants: Synthesis and Characterization of Aromatic Dilithionickeloles from 1,4‐Dilithio‐1,3‐butadienes and [Ni(cod)2] 下载免费PDF全文
Junnian Wei Prof. Dr. Wen‐Xiong Zhang Prof. Dr. Zhenfeng Xi 《Angewandte Chemie (International ed. in English)》2015,54(20):5999-6002
Organolithium compounds can behave as reductants but never as oxidants in redox reactions. Reported herein is that 1,4‐dilithio‐1,3‐butadienes reacted with [Ni(cod)2] (cod=1,5‐cyclooctadiene) to deliver dilithionickeloles. Single‐crystal X‐ray structural analysis revealed a coplanar structure of dilithionickeloles with an averaging of bond lengths. XPS data confirmed the oxidation state of Ni in dilithionickeloles was Ni2+. 7Li NMR spectra of dilithionickeloles and theoretical calculations revealed a considerable aromatic character. In this redox reaction, the dilithio dianionic compounds behaved as formal oxidants, thus oxidizing Ni0 into Ni2+. These results demonstrated that organolithium compounds with π‐conjugation could be used as oxidants and could continue to accept extra electrons. 相似文献
996.
Dr. Thomas Pugh Dr. Andrew Kerridge Dr. Richard A. Layfield 《Angewandte Chemie (International ed. in English)》2015,54(14):4255-4258
Deprotonation of the yttrium–arsine complex [Cp′3Y{As(H)2Mes}] ( 1 ) (Cp′=η5‐C5H4Me, Mes=mesityl) by nBuLi produces the μ‐arsenide complex [{Cp′2Y[μ‐As(H)Mes]}3] ( 2 ). Deprotonation of the As? H bonds in 2 by nBuLi produces [Li(thf)4]2[{Cp′2Y(μ3‐AsMes)}3Li], [Li(thf)4]2[ 3 ], in which the dianion 3 contains the first example of an arsinidene ligand in rare‐earth metal chemistry. The molecular structures of the arsine, arsenide, and arsinidene complexes are described, and the yttrium–arsenic bonding is analyzed by density functional theory. 相似文献
997.
Back Cover: Cycloparaphenylene‐Based Ionic Donor–Acceptor Supramolecule: Isolation and Characterization of Li+@C60⊂[10]CPP (Angew. Chem. Int. Ed. 12/2015) 下载免费PDF全文
998.
Energy Storage Materials from Nature through Nanotechnology: A Sustainable Route from Reed Plants to a Silicon Anode for Lithium‐Ion Batteries 下载免费PDF全文
Dr. Jun Liu Peter Kopold Prof. Peter A. van Aken Prof. Joachim Maier Prof. Yan Yu 《Angewandte Chemie (International ed. in English)》2015,54(33):9632-9636
Silicon is an attractive anode material in energy storage devices, as it has a ten times higher theoretical capacity than its state‐of‐art carbonaceous counterpart. However, the common process to synthesize silicon nanostructured electrodes is complex, costly, and energy‐intensive. Three‐dimensional (3D) porous silicon‐based anode materials have been fabricated from natural reed leaves by calcination and magnesiothermic reduction. This sustainable and highly abundant silica source allows for facile production of 3D porous silicon with very good electrochemical performance. The obtained silicon anode retains the 3D hierarchical architecture of the reed leaf. Impurity leaching and gas release during the fabrication process leads to an interconnected porosity and the reductive treatment to an inside carbon coating. Such anodes show a remarkable Li‐ion storage performance: even after 4000 cycles and at a rate of 10 C, a specific capacity of 420 mA h g?1 is achieved. 相似文献
999.
The Donor‐Base‐Free Aggregation of Lithium Diisopropyl Amide in Hydrocarbons Revealed by a DOSY Method 下载免费PDF全文
M.Sc. Roman Neufeld Dr. Michael John Prof.Dr. Dietmar Stalke 《Angewandte Chemie (International ed. in English)》2015,54(24):6994-6998
Lithium diisopropyl amide (LDA) is a very prominent reagent that plays a key role in organic synthesis, serving as a base par excellence for a broad range of deprotonation reactions. However, the state of aggregation in solution in the absence of donor bases was unclear. In this paper we solved this problem by employing DOSY NMR experiments based on a newly elaborated external calibration curve (ECC) approach with normalized diffusion coefficients. 相似文献
1000.
Stereoselective Retentive Domino Transmetalations of Secondary Alkyllithium Compounds to Functionalized Secondary Alkylcopper Reagents 下载免费PDF全文
Kohei Moriya Meike Simon Rasmus Mose Prof. Dr. Konstantin Karaghiosoff Prof. Dr. Paul Knochel 《Angewandte Chemie (International ed. in English)》2015,54(37):10963-10967
Functionalized secondary alkyllithium reagents obtained by I/Li exchange from the corresponding secondary alkyl iodides undergo two successive transmetalations with Me3SiCH2ZnBr?LiBr and CuBr?2 LiCl?Me2S to provide functionalized secondary alkylcopper compounds with high retention of configuration. These alkylcopper derivatives react further with electrophiles such as alkynyl esters, acid chlorides, allylic chlorides, ketals, ethylene oxide, and 3‐iodocyclopentanone with high retention of configuration. A related sequence of transmetalations with MeMgI and LaCl3?2 LiCl allows a retentive addition of secondary alkyllithium reagents to acetone. The influence of the solvent on the configurational stability of secondary alkylzinc reagents is described. 相似文献